On 2012-11-20 13:06, Trevor Cordes wrote:
On 2012-11-20 Gilbert E. Detillieux wrote:
I wouldn't be so sure about that, unless you've really checked that closely, and/or disabled most system services that might affect
I have tried to monitor things closely with top, especially sorted by memory usage. I'm doubtful it's a change in usage that is causing this because I have such a big (5GB) usual buffer/cached/free area, and I really am doing nothing during these tests that would chew through 5GB of files or data. For instance, my cached line in top stays roughly the same. That would mean that it would have to be 4GB+ of other files being read to flush out the stuff I want cached.
I run a lot of services but I've disabled all "automatic" and "desktop" stuff, for instance I run no desktop index program, or anything like that.
It used to be that the only thing that would "uncache" my files is watching some videos that obviously can chew through a few GB cache quickly.
You might also be interested in this article...
http://www.admin-magazine.com/Articles/Tuning-Your-Filesystem-s-Cache/
Specifically, the part about the vmtouch command and the "-dl" (daemonize and lock) option. It would allow you to lock your large file(s) into memory while you work on them, I think. That way, other system activity won't evict your cached pages.
Have you tried setting swappiness all the way to 100? Did that have no effect?
I'll try that next. The more I read about swappiness, the more I get confused whether in my case I want it set closer to 0 or closer to 100. I thought 100, but it really doesn't frame things in terms of cache/buffers.
I think you'd want to go to 100, to encourage more swapping, which would have the side-effect of (hopefully) leaving more memory available for disk caching.